1. Field of the Invention
The present invention relates to inner cylinder locks and more specifically, to a modification in a bolt of the inner cylinder lock. This modification or improvement in the bolt reduces the risk of the unauthorized opening of the inner cylinder lock even if the forward case of the lock is removed.
2. Description of the Prior Art
Inner cylinder locks are well known in the art, and various methods have been proposed to prevent unauthorized access into the areas or enclosures that they protect.
U.S. Pat. No. 4,143,528 issued on Mar. 13, 1979 to Gunter Weber et al. discloses an anti-theft locking device wherein if the locking cylinder is removed by an unauthorized person, a lever that abuts the cylinder is freed to swivel, thus releasing a spring biased bolt that moves into the locked position.
In my prior U.S. Pat. No. 4,977,768 issued on Dec. 18, 1990, a pick resistant axial split-pin tumbler lock is disclosed. A bolt is movable in the rear case of the lock into a locked or unlocked position, but no provision is made to prevent unauthorized access to the secured enclosure by simply removing the entire front casing of the inner cylinder lock.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.